Theoretical exploration of uranyl complexes of a designed polypyrrolic macrocycle: Structure/property effects of hinge size on Pacman-shaped complexes

Qing Jiang Pan, Samuel O. Odoh, Georg Schreckenbach, Polly L. Arnold, Jason B. Love

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

A polypyrrolic macrocycle with naphthalenyl linkers between the N 4-donor compartments (L 2) was designed theoretically according to its experimentally-known analogues with phenylenyl (L 1) and anthracenyl (L 3) linkers. The uranyl and bis(uranyl) complexes formed by this L 2 ligand have been examined using scalar-relativistic density functional theory. The calculated structural properties of the mononuclear uranyl-L 2 complexes are similar to those of their L 1 counterparts. The binuclear L 2 complexes exhibit a butterfly-like bis(uranyl) core in which a linear uranyl is coordinated in a side-by-side fashion to a cis-uranyl unit. The calculated UO bond orders in the uranyl-L 2 complexes indicate partial triple bonding character with the only exceptions being the U-O endo bonds in the U 2O 4 core of the butterfly-shaped binuclear complexes. Overall, the bond orders agree with the trends in the calculated UO stretching vibrational frequencies. Regarding the bis(uranyl) L 1, L 2 and L 3 complexes, the phenylenyl-hinge L 1 complexes adopt a butterfly-like and a T-shaped isomer in the oxidation state of U(vi), but only a butterfly-like one in the U(v), which differs from that of the naphthalenyl-hinge L 2 complexes as well as the lateral twisted structure of the anthracenyl-hinge L 3 complexes. The intramolecular cation-cation interactions are found in the L 1 and L 2 complexes, but are absent in the L 3 complexes. Finally, using model uranyl transfer reactions from the L 1 complexes, the formation of the mononuclear L 2 complexes is calculated to be a slightly endothermic process. This suggests that it should be possible to synthesize the L 2 complexes using similar protocols as employed for the L 1 complexes.

Original languageEnglish (US)
Pages (from-to)8878-8885
Number of pages8
JournalDalton Transactions
Volume41
Issue number29
DOIs
StatePublished - Aug 7 2012

Fingerprint Dive into the research topics of 'Theoretical exploration of uranyl complexes of a designed polypyrrolic macrocycle: Structure/property effects of hinge size on Pacman-shaped complexes'. Together they form a unique fingerprint.

Cite this